1. Field of the Invention
This invention relates generally to the handling of fragile devices such a semiconductor dice and more particularly to a pick up pencil assembly which has low contact mass and controlled deacceleration.
2. Description of the Prior Art
Apparatus for the selection and sorting of semiconductor chips is known. U.S. Pat. No. 3,720,309 discloses on such apparatus. This patent shows a wafer of semiconductor material fractured into individual chips mounted on an adhesive tape and positioned over a needle housing which contains an extendable needle. The needle housing is surrounded by a vacuum collar for holding down the chips surrounding the chip to be selected. The needle, as it extends out of the housing, ruptures the tape and pushes the selected chip off the tape and against a probe rigidly held a fixed distance above the needle housing.
Because the chip must traverse this fixed distance from the housing to the probe on the point of the needle, slipage or twisting or canting of the chip can easily occur with resulting adverse effects to the chip such as smearing of the contacts on the face of the chip or even breakage of the chip. Also uneven rupture of the tape can cause the contact force of the chip with the probe to vary considerably also resulting in damage to the chip. Additionally as the chips are removed from the tape the holes in the tape made by the needle reduces the effect of the vacuum collar which in turn permits still further shifting and twisting of the chips.